1. Field of the Invention
This invention relates to hydraulic systems which are used to power heavy machinery. More specifically, this invention relates to an improved tank for holding hydraulic oil which is used in hydraulic systems.
2. Description of the Prior Art
Hydraulically-powered equipment is common in modern industry, and is especially well-suited for use on vehicular systems which require the efficient transmission of powerful forces. For example, hydraulic operating systems are used to turn mixing drums on mobile cement mixing and dispensing systems which are manufactured by McNeilus Truck and Manufacturing, Inc. of Dodge Center, Minn., which is the assignee of this invention.
In a hydraulic system, an oil tank is typically used to store hydraulic oil while the oil is not being used. In many systems, hydraulic oil is constantly circulating through such a tank. During recirculation, it is advantageous to promote mixing of the oil within the tank to efficiently cool the oil and to achieve its maximum service life.
While existing designs of hydraulic tanks have proven satisfactory in the past, it is recognized that any reductions in the overall weight of such tanks would be advantageous, particularly in vehicle-mounted systems. Likewise, improvements which reduce the manufacturing costs of such tanks would constitute important advances in the art, since they would make hydraulic systems even more economical to purchase and maintain.
It is clear that there has existed a long and unfilled need in the prior art for an improved hydraulic fluid tank which promotes better internal circulation of hydraulic fluid during use, is lighter in weight and is less expensive to manufacture than oil tanks which were heretofore known.